The invention is in the field of mechanical engineering, in particular micromechanics, and addresses fluid pumps which work with rotating impeller blades and are particularly configured for use in areas which are difficult to access.
Pumps of this type can be used, for example, in the medical field and can also have particularly small construction shapes for this purpose.
A special application of micropumps is, for example, the assistance for the pump force of the human heart. Pumps used in this area are usually introduced into the body through blood vessels and are optionally operated in a chamber of the heart.
A plurality of such pumps have already become known which have different constructional shapes. An axial flow pump has become known, from WO 98/53864, and equally from EP 1 738 783 A1, which in each case has a rotor in the form of a rigid shaft, said rotor being provided with impeller blades and said shaft being outwardly journalled in a stator. The drive can be directly integrated into the stator and the rotor as an electromagnetic drive.
Pumps of this type have the disadvantage that they have a large diameter in relation to the pumping capacity and can hardly be introduced through a blood vessel.
In contrast to this, a rotor is known from WO 03/013745 A2 which has a smaller diameter in a compressed state than in an expanded state and which has an expandable rotor blade which expands in operation by the fluid counterpressure of the blood.
Other rotors which have become known likewise have impeller blades which are expandable for operation, for example by joints or by elastic deformability of the impeller blades.
A particular problem in this respect is that the impeller blades are usually fastened to a central neck and are rotationally drivable and also movably pivotable from this; that the impeller blades thus have to be flexible, but have a certain stiffness or a restriction in its movability, on the other hand, to exert the required pressure onto the fluid for conveying.